Appendix E
Key Questions and Eligibility Criteria
Key Question: What is the association between body mass index (BMI) and chronic disease, including all-cause mortality?
Population |
|
Interventions/exposures and comparators | Body weight category (by BMI, Z-score): overweight, obese, underweight, normal weight |
Study designs (of primary studies included within the systematic reviews) |
Include:
Exclude:
Systematic reviews must include a meta-analysis |
Timing | No minimum “treatment” or exposure duration required No minimum follow-up duration (to when outcome is measured) |
Setting | Restrict to high- and upper middle-income countries Restrict to systematic reviews published 2017 or later |
Outcomes |
|
Key Question: What is the effect of BMI (and other measures of adiposity) on energy balance or energy expenditure?
Population |
|
Interventions/exposures and comparators |
|
Study designs (of primary studies included within the systematic reviews) |
Include:
Exclude:
|
Timing |
|
Setting |
|
Outcomes |
|
NOTE: BEE = basal energy expenditure; BMI = body mass index; BMR = basal metabolic rate; HOMA-IR = Homeostatic Model Assessment of Insulin Resistance; REE = resting energy expenditure; RMR = resting metabolic rate.
Key Question: What is the association of body composition with metabolic efficiency (energy usage/expenditure)?
Population |
|
Interventions/exposures and comparators |
|
Study designs (of primary studies included within the systematic reviews) |
Include:
Exclude:
|
Timing |
|
Setting |
|
Outcomes |
Usage/expenditure must be measured (e.g., DLW, direct and indirect calorimetry)
|
NOTE: DLW = doubly labeled water; DXA = dual-energy X-ray absorptiometry; FFM = fat-free mass; FM = fat mass.
Key Question: How does the increase in tissue deposition associated with growth during infancy, childhood, adolescence, pregnancy, and lactation influence, affect, or contribute to energy requirements?
Population |
|
Interventions/exposures and comparators | The life stage of infancy, childhood, adolescence, pregnancy, and lactation |
Study designs |
Include:
Exclude:
|
Timing |
|
Setting |
|
Outcomes |
|
NOTE: DLW = doubly labeled water
Key Question: What is the impact of race or ethnicity on energ expenditure?
Population |
|
Interventions/exposures and comparators | Race or ethnic group |
Study designs (of primary studies included within the systematic reviews and primary studies) |
|
Timing |
|
Setting |
|
Outcomes |
|
NOTE: BEE = basal energy expenditure; BMR = basal metabolic rate; REE = resting energy expenditure; RMR = resting metabolic rate.
Key Question: What is the association of macronutrient composition of the diet on metabolic efficiency (energy usage/expenditure)?
Population |
|
Interventions/exposures and comparators |
Diets with different macronutrient composition
|
Study designs (of primary studies included within the systematic reviews) |
Include:
Exclude:
|
Timing |
|
Setting |
|
Outcomes |
Usage/expenditure must be measured (e.g., DLW, direct and indirect calorimetry)
|
NOTE: DLW = doubly labeled water.
Key Question: In the U.S. and Canadian free-living population, what is the degree of systematic bias or random error of energy intake as assessed by diet records, 24-hour recalls, food frequency questionnaires, compared to doubly labeled water? Does the bias differ by age group, sex, body weight status, body mass index (BMI), social economic status, race, ethnicity, presence of chronic disease, or physical activity level?
Population |
|
Interventions/exposures and comparators | Participation in a doubly labeled water study measuring usual dietary intake |
Study designs (of primary studies included within the systematic reviews) |
|
Timing |
|
Setting |
|
Outcomes | Percent of misreporting of energy intakes |
Key Question: How do physical activity and energy expenditure change across the life span?
Population |
|
Interventions/exposures and comparators | Different age or age categories |
Study designs (of primary studies included within the systematic reviews) |
Include:
Exclude:
|
Timing |
|
Setting |
|
Outcomes |
|
NOTE: BMI = body mass index; kcals = kilocalories; METs = metabolic equivalent of task.
Key Question: What is the relationship between different measurements of physical activity and energy expenditure?
Population |
|
Interventions/exposures and comparators | Physical activity measurement method |
Study designs (of primary studies included within the systematic reviews) |
Include:
Exclude:
|
Timing |
|
Setting |
|
Outcomes |
|
|
NOTE: BMI = body mass index; kcals = kilocalories; METs = metabolic equivalent of task.
Key Question: What is the association between weight change an chronic disease outcomes?
Population |
|
Interventions/exposures and comparators |
|
Study designs (of primary studies included within the systematic reviews) |
Include:
Exclude:
|
Timing |
|
Setting |
|
Outcomes |
|
Key Question: What is the effect or association of weight cycling on metabolic efficiency (energy usage/expenditure) and health outcomes?
Population |
|
Interventions/exposures and comparators | Weight cycling Exclude any cointerventions/coexposures (e.g., low fat + vitamin B12 vs. high fat; physical activity) |
Study designs (of primary studies included within the systematic reviews) |
Include:
Exclude:
|
Timing |
|
Setting |
|
Outcomes |
|
NOTE: BEE = basal energy expenditure; BMI = body mass index; BMR = basal metabolic rate; HOMA-IR = Homeostatic Model Assessment of Insulin Resistance; REE = resting energy expenditure; RMR = resting metabolic rate.
Key Questions:
What level of calorie intake is needed to produce weight gain in individuals with underweight? What amount of calorie intake (deficit) is necessary to produce weight loss in individuals with overweight or obesity? What level of calorie intake is needed to maintain weight across the weight spectrum?
Population |
|
Interventions/exposures and comparators | Measure of caloric intake Exclude any cointerventions/coexposures (e.g., low fat + vitamin B12 vs. high fat; physical activity) |
Study designs (of primary studies included within the systematic reviews) |
Include:
Exclude:
|
Timing |
|
Setting |
|
Outcomes |
|
NOTE: BEE = basal energy expenditure; BMI = body mass index; BMR = basal metabolic rate; HOMA-IR = Homeostatic Model Assessment of Insulin Resistance; REE = resting energy expenditure; RMR = resting metabolic rate.